Acharei Mot, Section 1
1) (Vayikra 16:1) ("And the L–rd spoke to Moses after the death of the two sons of Aaron when they drew near before the L–rd and they died,") "And the L–rd spoke to Moses after the death of the two sons of Aaron": What is the intent of this ("two")? Because it is written (Vayikra 10:1) "And the sons of Aaron took, Nadav and Avihu, each his coal-pan" — "the sons of Aaron" — they did not seek counsel from Aaron; "Nadav and Avihu" — they did not seek counsel from Moses; "each his coal-pan" — each by himself; they did not take counsel from each other. Whence is it derived that just as the transgression of the two was identical, so the death of the two was identical? From "after the death of the two sons of Aaron."